My first impression after getting the Linn ADS (Cara 6) was the low level detail extraction, I did not realize how much information was there previously. It also made my HD650 and K501 sing again (foot tapping, PRaT) after living with CEC TL51XR as primary source for several months.
I don't know how to describe the sound signature of Linn ADS , but after updating to the latest firmware, Cara 9, which delivers more music, more transparent, more details, and more rhythm. Maybe it's purely psychological, but I am happy with what I am listening everyday now. The timbre of the instruments also sounds real and natural. With Grado HP1000, which some said is "boring" and flat, is really musical and enjoyable for extended periods of listening without fatigue
Thanks

Thank you for your kind words, my pleasure
Thanks tbln, you know, the music always comes first
Sonq, is your WA6 maxed out? Does it have a more tubey sound compare to Zana Deux in your memory?
Hand itchy to try the WA5-LE

Thank you heady Sadly I don't have other amp for a comparison The result of HD800 with Zana is rather satisfying. I could easily live with the combo and not looking further (still can't decide if I need another headphone )
Hey Sonq,
Thank you but I don't have the PS1 anymore… The PS1000 doesn't sound very liquid in my current setup, comfort-wise, PS1000 is less heavy and suitable to wear for some extended period of time and my external ears won't turn red (this was the case with PS1, wore after 30 mins…).
I did try the bagel pads on PS1, better comfort but sound quality decreased big time. PS1000 has better soundstaging/imaging and I think PS1000 also better for a wider genres of music.

As promised, having borrowed this two statement headphones for over a month, after the initial excitement is gone, I am just started to post some comparative comments and observations regarding some of the best dynamic headphones in current production.
1. Some background & caveats
I am always a Grado fan and Grado SR-60 was the first headphone that got me started. I only started to enjoy and appreciate Sennheiser HD600/650 after owning some quality amps such as GCHA, RPX-33 and Zana Deux. I love the creamy and slightly but not overly dark sound signature of HD650 so much that I prefer to stick with its own stock cable when driving through Zana Deux. I am also a detail freak, a balance between transparency and "musicality" (the ability to enjoy the music) is equally important to me. Disclaimer: all impressions are solely mine and wholly subjective.
2. Music used:
Armik - Rubia
Chet Baker - Chet
Koji Tamaki - ワインレッドの心
Francis Albert Sinatra & Antonio Carlos Jobim
Shawn Colvin - A Few Small Repairs
Kenji Kawai - Ghost in the Shell
J.J. Cale - Troubadour; To Tulsa And Back
Wes Montgomery - Bumpin' At Sunset
Dave Brubeck Quartet - Jazz Impressions of Eurasia
Charles Mingus - Mingus Ah Um
Jeff Buckley - Mystery White Boy (Live)
Zhou Zhi-Yong - The Great Yellow River
Dave's True Story - Nature
3. Comparison/The Sound:
I used a couple of songs that I was extremely familiar in order to compare the 2 headphones.
The first time when I listened to the HD800, wow! What a soundstaging! Both headphones have remarkable imaging and soundstaging. In many music I tested, HD800 seems to have a wider soundstaging and more 3-D feeling. However, after the initial excitement is gone, I found myself to prefer the soundstaging on Grado HP1000/HP2, a more coherent, natural and realistic imaging.
I must say, both headphones are highly resolving. Previously unheard background voices with HD650, all the sudden come into tune, guitar strings and instruments not heard before can be heard clearly individually. Yes, that made me very excited to crank up the volume. I was also aware that the resolution did not necessary translate into "noise" that made music listening fatigue. The PS1000 sounded really good even straight out of computer sound card and foobar2000, not much flesh and resolution to talk about. Only when I used my headphone setup to put it under test, the challenge comes. It deserves better recordings and low noise 6SL7 NOS tubes. And you can imagine the computer sound card will not have enough drive for HD800 so I had skipped this.
These headphones are very fast, have apparent attack/decay and overall good transient response. For the genres of music I listen, PS1000 is more foot-tapping good.
3a. The midrange:
For my taste, I prefer the HD800 over PS1000 with regards to vocal and midrange. Both headphones have detailed and airy vocals. But I feel that the vocals on PS1000 sounds slightly sterile and less intimate. On the other hand, HD800 sounds so much sweeter and engaging with fuller body. It's very inviting and feel like the singer is whispering into my ears. However, tube rolling does help a bit here for PS1000. When I used NU JAN-CNU-6SL7GT black glass, it adds a bit more warmth to the midrange on PS1000.
3b. The treble:
When dealing with treble/highs, my body will give me warning when it is being too much: physical discomfort & tiring. At no point in time did I encounter any sibilance with either headphone. From the frequency response graph, it looks like the PS1000 has a similar treble energy like the GS1000. But IMO in most case, it doesn't sound like GS1000 and the highs actually texturing well and not fatigue nor bright to listen. Only when I changed a driver tube to a1950's Brimar 6SL7GT, black base, orange label & "D" getter, the PS1000 changed its face to really "fierce" and tiring to listen with aggressive treble energy. Again, system matching does play important part. At same volume on the amplifier, the PS1000 is a bit brighter when compare to HD800. The HD800 is no way dark or "veil" sounding here.
3c. The bass:
For me, I really prefer PS1000 over HD800 in bass performance. I won't say the HD800 is bass-shy, because on recording with huge bass (Great Yellow River, track 3) it still sound huge but with less control and definition; when I listen to "Making the Cyborg" & "Reincarnation"from "Ghost in the shell", I could feel the bass drum hitting hard. The bass of HD800 is more about quality; while the bass performance of PS1000 is quality as well as quantity. The bass on PS1000 goes lower, tighter, very well-controlled & better defined and yet still offering a very nice separation from the rest of frequency response. It's not boomy, and never overwhelmed like the PS-1.
4. Conclusions?
Disclaimer: all impressions are solely mine and wholly subjective. For the types of music (jazz, blues, vocals) I listen, Grado really suits me better. It recreates the feeling of smokey, laid back mood of a jazz club naturally. I'd say in order to get to this level of performance (be it in anything), requires a high degree of specialization which necessarily results in application specific strengths/weaknesses - these, then, are ultimate the deciding factors. Thus, it becomes nearly impossible for one to be anything more than a genre (or two) specific leader.
I really like the HD800, one of the best dynamic headphones in production. However, some facts are pulling me back. Due to the low distortion and larger transducer of HD800, I found myself tend to crank up the volume when I listen to it. It really sounds great at greater volume (slightly over 9 o'clock) but I value my hearing more than the sound quality. Will I get the PS1000? Hmm no, one of the reasons is the shorter headphone cable (compared to other Grados) and that the Grado extension cable also degrades its sound quality. Another reason is the look/appearance reminds me a lot of the GS1000, the only high-end Grado I had owned, revisited several times, and did not like.
5. Equipment:
Source: Linn Akurate DS (Cara 9, 3.9.1) w/ dynamik power supply (Gregg Straley's power cord)
IC: Barradio's DIY IC
Amplifier: Zana Deux (Acrolink 6N-P4030 with Oyaide P/C-004)
(Driver : Tungsol 6SU7GTY; Power triodes: 1969's 6C33C-B "winged-C"; Rectifier: 6D22s with C logo)
Power: PS Audio Duet (Blacksand Violet Z1)
Headphones: HD800 (stock cable), PS1000
6. Reference:
1. J. G. Holt. "Sounds Like? An Audio Glossary", Stereophile, 1993.
http://www.stereophile.com/reference/50/

This is really tough, because GS1000 is very picky about the amp used. I sold it 3 years ago and could not be happier. I had owned Grado PS-1 for two years, and in my limited experiences, I feel that the Stax Omega 2 MKI with SRM-007t has a very similar liquid feel and effortless sound...
If you could increase your budget a bit more, I would suggest Cary Xciter Amp. The designer used GS1000 as his main reference of choice to tune the circuit. A friend, who is also a fan of PS-1 after hearing mine, bought the PS-1000 to use with Cary Xciter Amp and is very happy about it. I've read pink fish media, some people also like their GS1000 with Naim Headline 2 with upgraded power supply (HiCap).

After updating to the latest Cara 9 for Linn DS, HD800 w/ stock cable win hands down
HD800 is so sensitive to the change of source. I can't believe it made big difference simply by updating the firmware... transparency, silky smooth, REAL, imaging, resolving, effortlessly, engaging, musical.... you name it

One man's meat is another man's poison
A bunch of girls gathered at my place and I let them listened to both HD800 and PS1000, they have zero interest in headphone-fi but they all prefer PS1000 to HD800 for the sound, and like HD800 for the comfort. After knowing the prices, they are like As expected huh..
I had very favorable initial impression for HD800; only after listening to PS1000 for a few days and when I went back to HD800, I missed the transparency and the airiness of PS1000. They seem lacking in HD800 and they are simply different sounding. One thing I don't like about PS1000 is the shorter headphone cable (compared to other Grados) and that the grado extension cable also degrade its sound quality . But I still stand behind my impression that the vocal/midrange of HD800 is fantastically good and more intimacy. HD800 also has bigger soundstage over PS1000. So far I too like the Tung Sol 6SU7GTY and 1944 Sylvania VT229 with both cans, sound more "authority"
Slowly coming back to headphone listening

Was the PS1000 you listened burned-in? Because it doesn't sound anything like GS1000 except for the soundstaging/imaging. The sound quality of PS1000 also better than GS1000, a lot more presence and body. The highs and bass are well-controlled and smoothed or textured, no piercing highs or boomy bass; the bass is still HUGE in my favorite recording ("The great yellow river" -KG1020-2) and am pleasantly surprised the PS1000 does control it very well.
And yes, I feel that the HD800 has sweeter midrange compared to PS1000.
I hope to listen to one can for a week, then go back to other for another week, see what would I miss
I see that you have RS1, flat pads on RS1 (I can't listen with bowls anymore - too thin and shrill sounding) and paired with Brimar CV1985 (brown base) is a combo made in heaven

no, I have on loan the PS1000 & HD800 for several days from a kind soul
The bowls on PS1000 actually make it more comfortable to wear than the PS1. Strange thing is I did not hear overwhelmed bass with PS1000, everything is good except that the midrange is not as lush as the PS1 in my memory... just need more time with it